I'm fully aware of the issue of having 40 bots following your character around causing potential crashes, and I agree that limitations need to be put in place to prevent that. I don't want to load a ton of bots and have them chase me around, but instead plop them down in one place and have them stay there. The only reason I'm suggesting a way to load multiple accounts from one admin character is to make it easier to test server stability. Being able to load up 60 bots instead of finding 60 real testers could help Mangos development.
As for security issues I don't think it's anymore of an issue than the security of normal player accounts. Aren't the account passwords encrypted? If they are or not it doesn't matter, a hacker would have to break into the db remotely to read them.
Here's an idea:
Have a field in a config file where you can name up to 5 extra accounts/passwords, much like databases, allowing you to load the characters from those accounts. Have a master "on/off" switch (0/1) for enabling bots from extra accounts. If it's enabled, bots will cease to have any AI and they will no longer follow you. All they'll do is stand in one place after you spawn them, therefore not causing any potential system crashes.